Dermal glands of Xenopus laevis contain a polypeptide with a highly repetitive amino acid sequence.
Mature dermal glands of Xenopus laevis contain storage granules with a characteristic ellipsoid shape. These granules contain, as a minor component, a heat-stable, acidic polypeptide with an apparent molecular mass of 75 kDa. Using antibodies against this protein, positive clones were isolated from a cDNA expression library prepared from skin of X. laevis. One of the cloned cDNAs encodes a pre-protein with a typical signal sequence and a mature part of 396 amino acids. The protein contains 33 copies of the sequence Gly-Gly/Glu-(Ala-Pro)2-4-Ala-Glu. Using the single-letter code for the four predominant amino acids, we have termed this polypeptide the APEG protein. Near its carboxy-terminus, one segment has been found with an amino acid sequence similar to that of spasmolytic polypeptide from porcine pancreas and to the human protein pS2.
Gmachl
M
M
Molecular Biology Institute, Austrian Academy of Sciences, Salzburg.
Berger
H
H
Thalhammer
J
J
Kreil
G
G
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D005088:Exocrine Glands / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D014982:Xenopus laevis / Q000378:metabolism*
D010455:Peptides; D004247:DNA